Non-woven fabrics are well known and have many varied uses, particularly in the textile industry. Such non-woven materials are useful as interliners for adhesive purposes or for support with fabrics and films. In many instances, the non-wovens can be made self-supporting and then used in fabricating garments, particularly where such garments are used one time and then discarded, such as in hospital operating rooms, and the like. These non-woven materials are made from a variety of fibers, such as, for example, cotton, wool, flax, glass, viscose rayon, cellulose acetate, acrylonitrile polymers (acrylics), polyamides (nylon), polyesters, etc. However, most of the known methods for producing non-woven fabrics from said fibers involve expensive and time consuming steps.
As an example of such time and expense is the manufacture of non-wovens from polymeric materials, such as acrylonitrile polymers, polyamides, polyesters, polyurethanes, and the like. First of all, the polymer must be spun in the form of a bundle of continuous filaments, treated and washed, cut into staple fibers, dried and baled. Thereafter, at a textile mill, the fibers are further treated, as by carding, to form a web in which the fibers are randomly distributed. Then the fibers are bonded together at the crossover points, i.e., wherever they cross or come in contact with another fiber. Such bonding is usually done with the use of adhesive compositions or by heating the fibers so that they soften sufficiently and fuse with other fibers at the contact points. Most of such non-woven fabrics tend to be stiff and have a harsh hand.
A recently developed process is being employed to overcome the aforesaid difficulties. In this process, the polymeric material is melted and passed through an extruder to a forming or shaping die. The polymeric material is extruded in the form of a film and immediately formed into a cellular or reticulated structure by means of a blowing agent. Overlapping of fibrils results in the structure and the material has the appearance of a non-woven fabric and is useful in the same end uses. This process has proved successful with many polymeric materials, such as polyethylene and the like. However, when making a lace-like structure from polyurethane, using said process, the hole size of the product formed is frequently too large and also nonuniform to give a commercially useful product. Polyurethanes are particularly useful for this kind of product since they impart good flexibility and have good binding properties. However, it is desirable to have a stiffer hand in the reticulate lace-like structure. Therefore, means of producing a reticulate lace-like structure from polyurethanes wherein the fiber structure changes sufficiently to give small holes and good uniformity thereof, along with a stiffer hand, is most desirable.